@tenshinoshi
Actually, there are people and cases like that.
https://www.theguardian.com/world/2017/aug/28/german-nurse-niels-hoegel-suspected-murdering-90-patients
>At least 90 people were killed at the hands of a German nurse who injected patients with cardiovascular medication in order to show off his resuscitation skills, a three-year police investigation has found.
And she wasn't caught for almost 15 years. Incompetent? Evil? Yes to both.